Gearbox housing and gearbox module

ABSTRACT

A gearbox housing with at least one first upper housing piece and a second lower housing piece, which may be detachably connected to each other. The gearbox housing has upper and lower housing pieces that are partially detachably connected to each other, with at least one rotating jointed connection between the upper housing piece and the lower housing piece, which are each arranged on a side described by the housing pieces in a view of the connection plane described by the profile and permitting a theoretical pivoting axis for pivoting the housing pieces relative to each other while maintaining the connection between the components. A catch is provided on the sides free of the rotating jointed connection.

BACKGROUND OF THE INVENTION

The present invention relates to a transmission housing and additionallya transmission modular unit.

Transmission housings are known in various embodiments. Reference ismade to DE 199 50 967 A1 as a representative, for example. Thisapplication discloses a control platform for a transmission modular unitwhich is positioned in the region of an operating means and/or oil sumpin the housing of the transmission modular unit, the oil sump beingenclosed by an oil pan. In this case, this region forms a lowertransmission housing part which is connected to an upper transmissionhousing part to form a modular unit—the transmission housing. Theattachment occurs via a fasteners, in the form of screws, for example.Since transmission modular units of this type are dimensioneddifferently for different uses, the problem of simple installation anduninstallation and/or easy accessibility to the inside of thetransmission for service repair and replacement work arises,particularly for heavy transmissions. The exact threading of sensorsrepresents a further problem during installation. An additionalauxiliary device, typically a lift truck, is necessary for installationand uninstallation for reasons of occupational safety, in particular forservice and repair and replacement actions, the separation and/oropening of the housing also not able to be performed without somethingfurther. For especially heavy embodiments of the transmission housing,it is also difficult to position the lower housing part exactly andattach it. If the transmission housing is suspended, the lower housingpart must be attached from below, exact positioning only being possiblewith difficulty because of the weight of the lower housing part, i.e.,this is only able to be performed with additional auxiliary means.Furthermore, removing the lower housing part also represents a specificset of problems, in particular, a safety device which supports the lowerhousing part and thus unloads the service personnel is also necessaryhere.

SUMMARY OF THE INVENTION

The present invention is thus based on the object of refining atransmission housing in such a way that the cited disadvantages areavoided, in particular even for transmission modular units fortransmitting higher powers, which have a corresponding weight because ofthe required dimensioning, permitting easy installation of thetransmission housing, and furthermore also allowing easy accessibilityto the power-transmitting elements. In addition, the transmissionhousing is to be distinguished by easy handling and service friendlinesswhen used to enclose power-transmitting elements, i.e., repair andreplacement actions are to be able to be performed without problems andmanage without additional auxiliary means.

The transmission housing comprises at least one upper housing part andone second lower housing part, at least partially enclosing an operatingmeans sump, which are detachably connected to one another. The upperhousing part is used to receive and mount the torque-transmittingcomponents. The housing is divided in the vertical direction. Accordingto the present invention, the lower housing part, which accommodates theoperating means, particularly the oil sump, and the upper housing partare only partially detachably connected to one another, in that they arecoupled to one another on one side via a pivot-point connection whichallows pivoting of one housing part in relation to the other housingpart around a theoretical pivot axis which lies in a connection planebetween the housing parts, and which is describable through thepositioning of the means for detachable connection, particularly thefasteners, the connection between the upper and lower housing parts inthe region of the theoretical pivot axis remaining in effect during thepivoting. The pivoting occurs at least essentially in the verticaldirection. For this purpose, at least one pivot point is providedbetween the upper and lower housing parts in the region of thetheoretical pivot axis, via which the connection and the pivot actionaround its axis of rotation occur. In this case, at least one safetymechanism is provided between the upper and lower housing parts at theside free of the articulated connection in the connection region. Thesafety mechanism is used, when the detachable connection between theupper and lower housing parts is unfastened, to limit the pivot angle abetween the upper and lower housing parts to a limiting angle β. Thesafety mechanism must be activated manually in this case in order toachieve a pivot around an angle greater than the limiting angle β untilthe maximum pivot angle is achieved. In this case, the maximum pivotangle α_(max) corresponds to the pivot angle of the lower housing partin relation to the upper housing part made possible by the pivot pointand the positioning of the transmission housing. When the transmissionhousing is positioned in a suspended position, the maximum pivot angleis additionally delimited by the suspension position of the transmissionhousing and by the position freely resulting because of the weight ofthe housing lower part, so that a pivot angle from >0 up through atleast 90° is achieved without additional auxiliary means. The pivotpoint is implemented in such a way that the pivot axis formed therebyextends over at least a part of one of the sides which describe thecontour of the housing lower part and/or housing upper part in theconnection region in a top view. The connection between the upperhousing part and the lower housing part is preferably implemented as ahinge connection in this case, i.e., a connection which allows pivotingof one component in relation to the other around a theoretical axislying in the connection plane which is describable by the connection,while maintaining the coupling between the upper housing part and thelower housing part.

The connection plane identifies the plane, observed in the verticaldirection, aligned in the horizontal direction or at an angle thereto,which is characterized by the contiguity of the faces of the upper andlower housing parts facing toward one another. The connection regionbetween the two housing parts may be characterized by

-   -   a) one connection plane or    -   b) multiple individual connection planes in a row.

There are no restrictions in regard to the concrete design of the hingeconnection. In this regard, all possible technical designs may be used,the hinge typically always being formed by a separate element which isconnected to the two housing parts, however.

There are multiple possibilities in regard to the design of the safetymechanism. However, care must be taken in the dimensioning in this casethat the safety mechanism must be suitable for holding the lower housingpart in its position in relation to the upper housing part whilepivoting around the limiting angle β. The safety mechanism itself istypically designed as a positive connection, preferably in the form of acatch or latch connection. This type of connection includes a firstelement which is connected to the upper housing part and a secondelement which is connected to the lower housing part, one of the twoelements including a recess, while the other has a projection whichengages therein. In the normal installation state, i.e., with aconnection between the upper and lower housing parts to form the closedtransmission housing, the safety mechanism is unloaded. The elementhaving a projection is guided into the recess with pre-tension in thiscase, preferably without exerting force on the element carrying therecess. The safety mechanism first comes to bear and/or the positiveconnection between the first and second element is first implementedwhen the lower housing part is pivoted in relation to the upper housingpart. The mechanism is designed in this case so that the positiveconnection is implemented upon reaching the limiting angle β. In thesimplest case, the element connected to the upper housing part isdesigned as a pawl, which is attached to the upper housing part so it ispivotable and which engages in a recess on a catch element connected tothe lower housing part. In this case, the pawl is fixed in its positionby the stop formed by the recess and, furthermore, by an elastic elementunder pre-tension. The elastic element is preferably designed as aspring unit. Only when the pre-tension is removed is the positiveconnection between the pawl and recess achieved. A reversal of theassignment of catch element in catch to the housing parts is alsoconceivable. The positive connection is then unfastened when additionalforce is exerted on the pawl. The positive connection is designed sothat a force exerted by an installer by hand is sufficient, this forcenot being able to be dimensioned too small for reasons of occupationalsafety.

According to an especially advantageous embodiment, the lowertransmission housing part is implemented in such a way that it alreadycontains the electronic and preferably also the hydraulic controldevices. In this case, an electronic control device is understood as thetotality of electronic control units, i.e., controllers, sensors, andconnections to the final control element. Electronic control unit isunderstood as the controller and/or a unit made of electrical andelectronic components to which the variables necessary for activatingthe transmission modular unit are supplied and which are processedtherein, and which outputs the manipulated variables produced from theinput variables in accordance with the desired activation procedure. Forthis purpose, the control unit typically includes multiple electricaland electronic components which are assigned and coupled to one anotherin accordance with the processing of the input variables to beperformed. Preferably, multiple components of this type are positionedtogether on at least one support plate and are enclosed by a controlunit housing. The possibility arises in this case that the support plateis completely integrated into the control unit housing or at least formsa partial wall region of the control unit housing.

In a further aspect of the present invention, the entire electroniccontrol device is integrated into the transmission housing and ispositioned in direct spatial proximity to the hydraulic control device.This means that multiple, preferably all devices for detecting avariable which at least indirectly characterizes the driving stateand/or the function of the transmission modular unit are also integratedinto the transmission modular unit and are positioned in spatialproximity to the hydraulic control device.

In this case, a hydraulic control device is understood as the hydraulicconnections between the detection means of an input variable and/or theelectrical control device and the final control elements, whichtypically have a pressure applied to them hydraulically, and theelements functioning as actuators and their coupling to the controlelements. Essentially all elements which it is necessary to actuate foractuating and/or setting the individual gears are included in this case.

Preferably, each of the control devices and/or units—electronic controlunit and hydraulic control device—is assigned a corresponding supportelement, which are connectable to one another to form a support device,so that a modular unit including at least the electronic control unitand the hydraulic control device may be formed. This may then be removedeasily as a whole from the transmission modular unit. A furtherpossibility is to position both—the electronic control device and thehydraulic control device—on a central support element and also form onemodular unit. In both cases, the entire modular unit made of supportelement(s), hydraulic control device, and electronic control unit isidentified as a control platform which may be offered as a commercialmodular unit. This may preferably be mounted in the housing lower part.

In a further aspect, a cooling device is assigned to the operating meansand/or control means and/or lubricant loop of the transmission modularunit and integrated into the housing. This may be designed in differentways, but typically includes either at least one cooler or a heatexchanger. The cooling device is preferably positioned next to one ofthe two devices—electronic control device and/or electronic control unitor hydraulic control device—and/or between the two. Optimum cooling ofthe electronic modular unit may thus be additionally achieved.

Preferably, the cooling device, electronic control device, and hydrauliccontrol device are positioned on a shared carrier element or are eachpositioned on their own carrier elements which may be assembled with oneanother to form a modular unit and thus produce a control platform.Preferably, a majority of the detection devices, typically implementedas sensors, for determining the input variables of the transmissionmodular unit to be processed in the control device or unit, are alsopositioned on the control platform and/or integrated therein, in orderto thus provide an even more compact modular unit which is easilyreplaceable. In this case, the control device would also be positionedalmost completely on the support element. The support element is thenintegrated into the transmission lower housing part.

In a further aspect of the present invention, the electronic controldevice is assigned a housing which is preferably implemented as sealedto a hydraulic fluid, such as oil, and/or another liquid. The controlunit may then also be positioned in the oil sump of the transmissionmodular unit. The possibility thus arises of subjecting the electricaland electronic components of the control unit to at least indirectcooling through the operating means located in the operating meansand/or oil sump of the transmission modular unit. The oil-tight designof the housing, however, requires an appropriately designed bushing onthe housing to implement the electrical connection between the controlunit and the sensors of the control device necessary for detecting thevariables, which at least indirectly characterize the current drivingstate and/or the driver command and/or further boundary conditions, andthe actuators to be activated using the control device for actuating theindividual elements of the transmission modular unit, for example, forimplementing the gear change and/or presetting input variables through ahigher-order control and/or regulating device. Preferably, theindividual contact elements or lines are guided through the control unithousing embedded in an electrically non-conductive and liquid-tightmaterial, so that penetration of harmful materials, such as oil, isprevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The achievement of the object according to the present invention will beexplained in the following on the basis of figures. The following isshown therein in detail:

FIG. 1 illustrates, on the basis of a perspective view, the possibilityof a design of a transmission housing according to the presentinvention;

FIGS. 2 a-2 c illustrate, on the basis of three views, a possibleembodiment of a safety mechanism;

FIGS. 3 a and 3 b illustrate, in a schematic, greatly simplified view, atransmission modular unit having a transmission housing according to thepresent invention.

FIGS. 4 a-4 c illustrate possible arrangements of the pivot pointconnections.

DETAILED DESCRIPTION

FIG. 1 shows a schematic, simplified illustration of the basicconstruction of a transmission housing 1 according to the presentinvention in the open state on the basis of a perspective illustration.Viewed in the vertical direction, this housing is implemented in atleast two parts and includes a first upper housing part 2 and a secondlower housing part 3, which at least partially accommodates an operatingmeans sump. The second lower housing part 3 is therefore also referredto as the oil sump 4. The first upper housing part 2 and the secondlower housing part 3 are detachably connected to one another. Accordingto the present invention, however, in the region of a connection plane 5provided in the vertical direction, the second lower housing part 3 iscoupled to the first upper housing part 2 via a pivot-point connection6, which allows pivoting of the oil sump 4 in relation to the firstupper housing part 2 around a theoretical axis 7 which lies in thisconnection plane 5 and describes a part of the connection between thefirst upper housing part 2 and the oil sump 4, while maintaining aconnection between the upper and lower housing parts. This alsoanalogously applies for pivoting the upper housing part 2 in relation tothe lower housing part 3. The pivot-point connection 6 is preferablyimplemented as a hinge connection 8 in this case. This is positioned onat least one side 9 of the contour described by the lower housing part 3and the side 10 of the contour described by the upper housing part 2 inthe connection plane 5 seen in the view from above. The overallseparation region which is describable by the separation and/or divisioninto the upper and lower housing parts 3 and 2 may be described by aconnection plane 5 or by a positive assembly of multiple individualconnection planes 5.1 through 5.n.

In the embodiment shown in FIG. 1, only one connection plane 5 isprovided in the vertical direction, which is aligned horizontally in theinstallation position. The faces of the upper and lower housing parts 3and 2 adjoining one another therein describe a geometric shape and/orcontour which is determined by multiple sides in a top view. Thepivot-point connection 6 is positioned on only one side in this case,the side 9 or 10 here. The hinge connection may be positioned on anyarbitrary diametrically opposing sides of the upper and lower housingparts 3 and 2 in this case. The connection to the remaining sides isperformed via means for detachable connection 11, which are to bepositioned and laid out on the transmission modular unit in accordancewith the dimensioning of the transmission housing 1. These typicallyinclude fasteners 12 which fix the position of the upper housing part 2and the lower housing part 3 in both the axial and vertical directions.

The remaining sides free of the pivot-point connection 6 are understoodas the sides of a contour which describes the geometry in a top viewresulting in a section in or parallel to the connection plane 5.

The pivot-point connection 6 preferably extends over a majority of theextension of the diametrically opposing sides 9 and 10 of the upper andlower housing parts 3 and 2 in a top view thereof in the connectionplane 5.

However, positioning multiple individual pivot-point individualconnections 6.1 through 6.n over the extension of the diametricallyopposing sides 9 and 10 at a specific distance a to one another, asshown in FIG. 4 a, or, for smaller transmission modular units, a singlepivot-point connection 6.4 b in the central region of the extension ofthe diametrically opposing sides 9.4 b and 10.4 b, as shown in FIG. 4 b,are also conceivable. A further theoretical arrangement of thepivot-point connection 6.4 c is to position it in the boundary regionbetween two sides 9.4 c and 10.4 c or 10 and 50, which adjoin oneanother at an angle, of the two housing parts 2.4 and 3.4, as shown inFIG. 4 c.

In order to avoid undesired rapid pivoting of the second lower housingpart 3 in relation to the first upper housing part 2 upon detaching thefasteners 12 when the housing 1 is suspended, at least one safetymechanism 13 is provided which allows partial pivoting of the lowerhousing part 3 in relation to the upper housing part 2 after thefasteners 12 are detached, but limits the pivot angle α to a limitingangle β by implementing a positive connection 14. This safety mechanism13 may be designed in different ways. The safety mechanism 13 may onlybe detached through further manual actuation, pivoting between the upperhousing part 2 and the lower housing part 3 up to the maximum pivotangle then being possible.

The safety mechanism 13 is shown in FIG. 2 a on the basis of a detailfrom a sectional illustration through a transmission housing 1 and isdesigned in the simplest case in such a way that it includes at leastone catch element 15 which is coupled fixed to one of the twotransmission components, in the case shown the upper housing part 2.This catch element 15 is preferably mounted on the upper housing part 2so it is pivotable. The catch element 15 also positively engages in acatch 16, which is positioned on and/or permanently connected to secondhousing part, in this case the lower housing part 3, the catch element15 merely engaging in the catch 16, i.e., being freely guided therebywithout receiving force, in the closed state between the first upperhousing part 2 and the second lower housing part 3. When the fasteners12 are detached and the second lower housing part 3 is pivoted inrelation to the first upper housing part 2 around a small pivot angleα₁, which corresponds to the limiting angle β, the catch element 15engages in the catch 16 and thus forms a positive connection. The catchelement 15 is held in its position in the axial direction by a springunit 17 for this purpose. The safety mechanism 13 may only be openedmanually by pivoting the catch element 15 in relation to the spring unit17 and thus against a pre-tension force. A corresponding embodiment fora safety mechanism 13 of this type is shown in FIGS. 2 a and 2 b in theexample of an embodiment as a pawl 18. The catch element 15 isimplemented as the pawl 18 in this case. This has a part, carrying abarb 19, which is aligned toward the second lower housing part 3 and/oris implemented on the end of the pawl 18 pointing toward it in theinstalled position. The pawl 18 is mounted on the upper housing part 2so it is pivotable, via a pivot bearing 20 in the case shown. The catch16 is formed by a sheet-metal element 21, for example, which isdetachably coupled to the lower housing part 3 via fasteners 22, theattachment preferably being in the region of the connection plane 5. Forthis purpose, the wall 23 of the second lower housing part 3 is designedlike a flange in the region of the connection plane 5, this flange 24also forming a further contact surface 26 for the sheet-metal element 21in addition to the connection surface 25 and/or contact surface for theupper housing part 2. The sheet-metal element 21 has at least one recess27 complementary to the pawl 18, through which the pawl 18 may beguided. The pawl 18 is fixed in its position in the recess 27 inrelation to the pivot bearing 20 by the spring unit 17, the recess 27simultaneously forming a stop 28 in the horizontal and verticaldirections for the pawl 18. In this case, the recess 27 has across-section which at least corresponds to the cross-section of thepawl 18 in the region of the barb 19. The barb 19 is directed in theaxial direction toward the stop 28 in this case, so that the face 29facing toward the sheet-metal element 21 comes to rest on the face 30 ofthe sheet-metal element 21 facing away from the upper housing part 2when the lower housing part 3 is moved and/or pivoted in relation to theupper housing part 2 or vice versa. Only through separate application offorce, i.e., manually by the service and maintenance personnel, forexample, to the pawl 18 and possibly also against the pre-tension forceof the spring unit 17, is the safety mechanism 13 detached by guidingthe pawl 18 through the recess 27. FIG. 2 b illustrates a view in theengaged, i.e., pivoted state around the limiting angle β.

FIG. 2 c illustrates a view from above of the safety mechanism 13 in thesection on the lower housing part 3.

The achievement of the object according to the present invention offersthe advantage that, independently of the concrete design of the lowerhousing part 3, particularly the oil pan 4, when used in a transmissionmodular unit 31, for a desired diagnosis or a necessary rapidreplacement of individual components, the entire transmission, i.e., thetransmission modular unit 31, must only be suspended for heavytransmissions, the first upper housing part 2 being suspended and thesecond lower housing part 3 simply being folded down. In accordance withthe design of the pivot-point connection 6 between the upper and lowerhousing parts 2 and 3, no further support is necessary for the lowerhousing part 3 after it is folded down and it may remain in the pivotedstate. The installer may thus reach the elements mounted in thetransmission housing 1 rapidly and very easily. A lift truck for thetransmission modular unit 31 is not necessary. Furthermore, complexthreading is dispensed with when installation is desired, i.e., closingthe housing 1, since the position of the housing parts 2 and 3 is fixedin relation to one another through the fixed coupling existing via thearticulated connection 6. The hinge connection 8 is positioned anddesigned in this case so that it extends over a significant part of thecorresponding sides 9 and 10, respectively, in order to achieveadditional fixing of the position between the upper and lower housingparts 2 and 3 in the horizontal direction.

FIG. 3 a shows a schematic and greatly simplified illustration of atransmission modular unit 31 having a transmission housing 1 designedaccording to the present invention in the unfastened state, while FIG. 3b shows the transmission modular unit 31 in the installed state. Onlythe input E and the output A, as well as the transmission housing 1 madeof first upper housing part 2 and second lower housing part 3 andfasteners 12, are shown.

The statements made in FIGS. 1 through 3 do not apply only totransmission housings 1 which only include a first upper housing part 2and a second lower housing part 3. Embodiments in which a housing coveris also provided in the axial direction are also conceivable.

According to an especially advantageous embodiment, additionally shownas an example in FIG. 1, the lower housing part 3 includes an electroniccontrol device 32 having a control unit 33 and a hydraulic controldevice 34, as shown in FIG. 5. Furthermore, according to an especiallyadvantageous embodiment, a cooling device 35 is additionally provided.There are multiple possibilities in this case in regard to the concretedesign of the electronic control device 32 and the hydraulic controldevice 34. In the simplest case, the electronic control device 32includes at least one electronic control unit 33, which has at least oneinput and one output. The input or inputs are coupled in this case todevices for at least indirect detection of at least one variable whichcharacterizes the mode of operation of the transmission modular unit.These devices are preferably implemented in the form of sensors. Theoutput or outputs are coupled to corresponding final control elements.These may be a component of the hydraulic control device or may becoupled to the outputs of the hydraulic control device. For thispurpose, the hydraulic control device 34 includes at least one,preferably multiple hydraulic control unit, which also have inputs andoutputs. The hydraulic control unit 34 may be implemented in this casein the form of electromagnetically actuatable valve devices. These areused to activate elements which are also referred to as actuators. Theseare in turn used to actuate individual clutch and/or brake devices ofthe transmission modular unit 31 to be actuated to implement a gearchange, for example. Preferably, all elements of the electronic controldevice 32 and the hydraulic control device 34 are positioned on asupport element 35, which is a component of the lower housing part 3and/or is formed by this part. It is thus possible to achieve thecomplete wiring of all actuators and sensors using the electroniccontrol unit 33, due to which no consideration must be taken of anypossible existing wiring between the upper housing part 2 and the lowerhousing part 3 when the lower housing part 3 is detached and/or pivotedin relation to the upper housing part 2. The support element 35, theelectronic control device 32, and the hydraulic control device 34 form acontrol platform 36 in this case. This may additionally include furtherfunctional elements, such as operating-means conveyance devices, filterdevices, etc. The electronic control unit 32 is typically positioned soit is shielded once again from the inner chamber 37 of the lower housingpart 3, particularly, if this part is used as an oil pan 4, in order toachieve appropriate encapsulation. A further possibility is to providethe second lower housing part 3 with a bulge provided in the inside 47in the direction of the upper housing part and to flange mount theelectronic control device 32 on the lower housing part 3 more or lessfrom the outside, the coupling to the other elements being implementedthrough the housing wall. There are multiple possibilities for possibleindividual concrete arrangements of the electronic control device 32,the hydraulic control device 34, and the individual sensors andactuators, as well as the functional elements. Reference is made in thisregard to the publication DE 199 50 967 A1. The content of thedisclosure of this publication in regard to the possible arrangements ofindividual elements of a control platform 36 is hereby included in itsentirety in the content of the disclosure of this application.

1. A transmission unit having an input, an output and a housing, saidhousing comprising: at least one upper housing part and at least onelower housing part pivotably connected to one another; at least one ofthe upper and lower housing parts receiving and mounting powertransmitting parts, said lower housing part including an oil sump; apivot connection between the upper housing part and the lower housingpart, the pivot connection being on a side of the housing in aconnection plane and defining a pivot axis in said plane whereby thehousing parts pivot relative to each other and remain connected;attachment elements on sides of the housing parts free from the pivotconnection detachably fastening said housing parts together in a closedposition; and a safety mechanism limiting the pivot angle of the housingparts about said axis to a limiting angle (β), said safety mechanismincluding at least one catch element pivotably mounted on one of thehousing parts and a catch mounted on the other housing part; wherein thecatch element is urged under a pretension force into alignment with thecatch when the housing elements are in the closed position and engagesthe catch when the attachment elements release the housing parts andpermit the housing parts to rotate to an open position to the limitingangle (β) to retain the housing parts at the limiting angle (β); saidcatch element selectively movable under force against the pretensionforce to disengage the catch and permit the housing parts to more fullyopen.
 2. The transmission unit according to claim 1, wherein the pivotconnection extends substantially over the entire extension of the sideof the housing to which the pivot connection is connected.
 3. Thetransmission unit according to claim 2, wherein the catch is positionedon the lower housing part and the catch element is positioned on theupper housing part.
 4. The transmission unit according to claim 2,wherein the catch element is a pawl having a barb.
 5. The transmissionunit according to claim 1, wherein the pivot connection is positioned ina middle region of the extension of the side of the housing to which thepivot connection is connected.
 6. The transmission unit according toclaim 5, wherein the catch is positioned on the lower housing part andthe catch element is positioned on the upper housing part.
 7. Thetransmission unit according to claim 5, wherein the catch element is apawl having a barb.
 8. The transmission unit according to claim 1,wherein the pivot connection conprises multiple individual pivotconnections which are connected to a side of the housing and spacedapart relative to one another over the extension of the side of thehousing to which the pivot connections are connected.
 9. Thetransmission unit according to claim 8, wherein the catch is positionedon the lower housing part and the catch element is positioned on theupper housing part.
 10. The transmission unit according to claim 8,wherein the catch element is a pawl having a barb.
 11. The transmissionunit according to claim 1, wherein the pivot connection is positioned inthe region of the intersection of two sides of the housing.
 12. Thetransmission unit according to claim 11, wherein the catch is positionedon the lower housing part and the catch element is positioned on theupper housing part.
 13. The transmission unit according to claim 11,wherein the catch element is a pawl having a barb.
 14. The transmissionunit according to claim 1, wherein the catch is positioned on the lowerhousing part and the catch element is positioned on the upper housingpart.
 15. The transmission unit according to claim 14, wherein the catchelement is a pawl having a barb.
 16. The transmission unit according toclaim 1, wherein the catch element is a pawl having a barb.
 17. Thetransmission unit according to claim 1, including an electronic controlunit and a hydraulic control unit combined into a control platform whichis mounted in the housing lower part.
 18. The transmission unitaccording to claim 1, wherein the power-transmitting parts are mountedin the upper housing part.